forrest@srs.UUCP (Forrest Durett) (10/10/85)
I am currently writing a program for a friend in the ROM Basic on the
Apple IIE and I am in need of a little help on a few things. I am a little
familiar with the Apple IIE and only slightly more familiar with the Rom Basic
that is included with the machine. First, I would like to be able to trap any
control characters inside the program which would halt execution (such as
CNTL C) of the program so that the program can be exited gracefully. Is this
possible and if so can someone enlighten me as to how? Second, has anyone
heard of or posses some kind of "down-loading" program which will take a Basic
program and convert it to machine code? I would appreciate any help that I
receive on these two matters. Currently I haven't a clue on either one.
Please respond by mail to me. Thank You.
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- Forrest Durett -
- ...{allegra,seismo}!rochester!srs!forrest S.R. Systems -
- Rochester, NY -
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To trap out Ctrl-c's, all you have to do is use an ONERR GOTO command somewhere in the beginning of your command...the control c will be interpretted as an "error" and will send the program to whatever line number you told it to GOTO.
ahby@meccts.UUCP (Shane P. McCarron) (11/02/85)
In article <9800015@uiucuxa> spk256@uiucuxa.CSO.UIUC.EDU writes: > >To trap out Ctrl-c's, all you have to do is use an >ONERR GOTO command somewhere in the beginning >of your command...the control c will be interpretted >as an "error" and will send the program to whatever >line number you told it to GOTO. > Unfortunately, this is a little misleading. Applesoft BASIC will leave a bunch of awful stuff on the stack when it jumps off to the error handler. This will cause terrible problems if you try to use the RESUME statement that apple has build in. In one of the early Applesoft BASIC manuals, there is a small assembly language program that you can call to clean up the stack. This may solve the problem, although I have never trusted it. There are also some locations in zero page that hold the location of the command that was being executed when the error occurred, as well as the stack pointer and some other information. These might be useful... Again, I don't think it would be infallible. The best scheme is to initialize your stack and restart the program if there is an error. Something like: 10 ON ERR GOTO 10000 ... 100 REM Main Program ... 10000 CALL 59415 : GOTO 100 : REM Call stkinit and restart the program. I hope this is a help. -- Shane P. McCarron Minnesota Educational Computing Corporation - Technical Services UUCP ihnp4!dicomed!meccts!ahby